1. Field of the Invention
The present invention relates to an IC card, and more particularly, to improvements in heat radiation and mechanical strength of the IC card.
2. Description of the Related Art
As developments have been recently made in fast and high-capacity cards, ICs to be mounted on the IC cards have also become faster and have increased power consumption so that the amount of heat generated by IC cards has increased. Furthermore, the IC cards are thin relative to their width and length. Since mechanical stress may be applied to IC cards, depending on how they are handled, insufficient rigidity resulting from that shape is a problem.
Such IC cards are disclosed in, for example, Japanese Patent Laid-Open Nos. 63-57296 and 2-255394 and Japanese Utility Model Laid-Open Nos. 62-202669, 3-61303 and 3-104721.
FIG. 19 is a sectional view showing an example of a conventional IC card. Referring to FIG. 19, a plurality of ICs, that is, IC packages 2 are mounted on a substrate 1 made of glass epoxy. The substrate 1 and the IC packages 2 constitute a module 3, which is fixed to a frame 4 made of resin. Conductive panels 5 and 6 are fixed to the frame 4 opposed to both sides of the substrate 1.
In such a conventional IC card, heat generated from the IC packages 2 is transmitted to the frame 4 and the conductive panels 5 and 6 through a space between the IC packages 2 and the conductive panels 5 and 6, and the substrate 1, and radiated therefrom into outside air. Therefore, heat radiation of the conventional IC card depends on the heat conductivity of these components. On the other hand, the mechanical strength of the whole IC card depends on the rigidity of the components.
In the conventional IC card having the above structure, since heat radiation and mechanical strength depend on characteristics of the components, it is difficult to maintain sufficient heat radiation and mechanical strength to speed up the response and increase the capacity of the IC packages 2.